Abstract

Parallel resonance generated by capacitive elements on the wind farm amplifies the current distortion caused by harmonic emission from the wind turbines and results in high voltage and current distortion through the transmission equipment connected to the grid. Similarly, series resonance amplifies the harmonic voltage distortion from the HV bus to MV bus, causing the same effect. Harmonic filters are used to screen out the unwanted harmonic effects on the wind farm. The switching activities of the harmonic filter bank may cause overvoltages on the onshore wind farm substation, thus, they are investigated in this paper with the aid of ATP/EMTP software. Temporary overvoltages caused by energising and de-energising of the filter were investigated to understand whether they exceed the withstand limits of the system. It was found that the overvoltages for both energization and denergization were beyond the power frequency withstand level. By then using statistical studies on the mitigation methods, it was found that the use of pre-insertion resistors and surge arresters greatly mitigated the overvoltage caused by energization.

M. Bollen, S. Mousavi-Gargari, and S. Bahramirad, "Harmonic resonances due to transmission-system cables," in Proc. of the International Conference on Renewable Energies and Power Quality, Cordoba, Spain, 2014.